U.S. patent number 8,894,747 [Application Number 14/019,328] was granted by the patent office on 2014-11-25 for system and method for removing carbon dioxide from an atmosphere and global thermostat using the same.
The grantee listed for this patent is Graciela Chichilnisky, Peter Eisenberger. Invention is credited to Graciela Chichilnisky, Peter Eisenberger.
United States Patent |
8,894,747 |
Eisenberger , et
al. |
November 25, 2014 |
System and method for removing carbon dioxide from an atmosphere
and global thermostat using the same
Abstract
A system for removing carbon dioxide from an atmosphere to
reduce global warming including an air extraction system that
collects carbon dioxide from the atmosphere through a medium and
removes carbon dioxide from the medium; a sequestration system that
isolates the removed carbon dioxide to a location for at least one
of storage and which can increase availability of renewable energy
or non-fuel products such as fertilizers and construction
materials; and one or more energy sources that supply process heat
to the air extraction system to remove the carbon dioxide from the
medium and which can regenerate it for continued use.
Inventors: |
Eisenberger; Peter (Princeton,
NJ), Chichilnisky; Graciela (New York, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
Eisenberger; Peter
Chichilnisky; Graciela |
Princeton
New York |
NJ
NY |
US
US |
|
|
Family
ID: |
40071181 |
Appl.
No.: |
14/019,328 |
Filed: |
September 5, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140004016 A1 |
Jan 2, 2014 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
12868915 |
Aug 26, 2010 |
|
|
|
|
12124864 |
May 21, 2008 |
|
|
|
|
11825468 |
Jul 6, 2007 |
|
|
|
|
11805477 |
May 22, 2007 |
|
|
|
|
11805271 |
May 21, 2007 |
|
|
|
|
Current U.S.
Class: |
95/139;
423/220 |
Current CPC
Class: |
B01D
53/1425 (20130101); B01D 53/1475 (20130101); B01D
53/1418 (20130101); B01D 53/62 (20130101); F23J
15/02 (20130101); B01D 53/04 (20130101); B01D
2251/304 (20130101); Y02A 50/2342 (20180101); Y02C
20/40 (20200801); Y02C 10/04 (20130101); B01D
2257/504 (20130101); B01D 2258/0233 (20130101); Y02A
50/20 (20180101); Y02C 10/06 (20130101); Y02E
20/326 (20130101); B01D 2251/604 (20130101); Y02E
20/32 (20130101); Y02C 10/08 (20130101) |
Current International
Class: |
B01D
53/02 (20060101) |
Field of
Search: |
;95/139 ;423/220 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1709553 |
|
Dec 2005 |
|
CN |
|
200 01 385 |
|
Sep 2000 |
|
DE |
|
20021180511 |
|
Feb 2002 |
|
EP |
|
20021234947 |
|
Aug 2002 |
|
EP |
|
19842543946 |
|
Oct 1984 |
|
FR |
|
58 122022 |
|
Jul 1983 |
|
JP |
|
198459216839 |
|
Dec 1984 |
|
JP |
|
03-245811 |
|
Jan 1991 |
|
JP |
|
06-062677 |
|
Mar 1994 |
|
JP |
|
07-051537 |
|
Feb 1995 |
|
JP |
|
11-244652 |
|
Sep 1999 |
|
JP |
|
2001-300250 |
|
Oct 2001 |
|
JP |
|
2003-326155 |
|
Nov 2003 |
|
JP |
|
2006-061758 |
|
Mar 2006 |
|
JP |
|
2006-075717 |
|
Mar 2006 |
|
JP |
|
WO9608678 |
|
Mar 1996 |
|
WO |
|
WO9829187 |
|
Jul 1998 |
|
WO |
|
WO2005026694 |
|
Mar 2005 |
|
WO |
|
WO2005037746 |
|
Apr 2005 |
|
WO |
|
WO2005108297 |
|
Nov 2005 |
|
WO |
|
WO2006009600 |
|
Jan 2006 |
|
WO |
|
WO2006036396 |
|
Apr 2006 |
|
WO |
|
WO2008042919 |
|
Apr 2008 |
|
WO |
|
WO2008063082 |
|
May 2008 |
|
WO |
|
Other References
Stolaroff, Joshuah et al. "A Pilot-scale prototype contractor for
CO2 capture from ambient air; cost and energy requirements." (2006)
www.ucalgary.ca/.about.keith/papers/84.Stolaroff.Air . . . . cited
by applicant .
English abstract, CN 1 303 910 A (Jul. 18, 2001) as cited in U.S.
Patent No. 7,795,175. cited by applicant .
English abstract, JP 2006-021989 A (Jan. 26, 2006) as cited in U.S.
Patent No. 7,795,175. cited by applicant .
Xu et al., "Preparations and characterization of novel CO2
`molecular basket` absorbents based on polymer-modified mesoporous
molecular sieve MCM-41." Microporus and Mesoporus Materials 62:
29-45 (2003) as cited in U.S. Patent No. 7,795,175. cited by
applicant .
International Search Report and Written Opinion of the
International Search Authority, dated Dec. 18, 2007, from
corresponding International application No. PCT/US2007/074615 as
cited in U.S. Patent No. 7,795,175. cited by applicant .
Hicks, Jason C. et al.; "Designing Adsorbents for CO2 Capture from
Flue GAs-Hyperbranched Aminosilicas Capable of Capturing CO2
Reversibly"; Feb. 2008; J. Amer. Chem. Soc., vol. 130, pp.
2902-2903. cited by applicant .
Gold, Blanchard; "Integrated Gasification Combined Cycle IGCC";
www.globalgreenhousewarming.com. cited by applicant .
Leal, Orlando; "Reversible adsorption of carbon dioxide on amine
surface-bonded silica gel"; 1995; Elsevier Science S.A., Inorganica
Chimica Acta 240, pp. 183-189. cited by applicant .
Dubey, "Science for sustainability: From capturing carbon dioxide
from air to environmental impact of a hydrogen economy," Apr. 2,
2003. cited by applicant .
Vaartstra, Brian A., et al., "Advances in Precursor Development for
CVD of Barium-Containing Materials." Mat. Res. Soc. Symp. Proc.
vol. 335, pp. 203-208, 1994 Materials Research Society. cited by
applicant .
Park, Jung Woo, et al., "Strontium B-diketonate complexes with
polyamine donor ligands: the synthesis and structural
characterization of [Sr(thd)2(L)]n (n=2; L=diethylenetriamine, n+1;
L=triethylenetetramine, tetraethylenepentamine and
tris(2-aminoethyl)amine) complex." Polyhedron 19 (2000) 2547-2555.
cited by applicant.
|
Primary Examiner: Jones; Christopher P
Attorney, Agent or Firm: Sutton; Paul J. Magidoff; Barry
G.
Parent Case Text
RELATED APPLICATIONS/CLAIM OF PRIORITY
This application is a continuation of, and claims priority from
application Ser. No. 12/868,915 filed Aug. 26, 2010, which is a
continuation of Ser. No. 12/124,864 filed May 21, 2008, which in
turn is a continuation-in-part of, and claims priority from, each
of the following US Patent Applications: (a) U.S. patent
application Ser. No. 11/825,468, filed on Jul. 6, 2007, which in
turn is a continuation-in-part of U.S. patent application Ser. No.
11/805,477, filed on May 22, 2007, which in turn is a
continuation-in-part of U.S. patent application Ser. No.
11/805,271, filed on May 21, 2007, (b) U.S. patent application Ser.
No. 11/805,477, filed on May 22, 2007, which is a
continuation-in-part of U.S. patent application Ser. No.
11/805,271, filed on May 21, 2007, and (c) U.S. patent application
Ser. No. 11/805,271, filed on May 21, 2007, all of which are
entitled "System and Method For Removing Carbon Dioxide From An
Atmosphere and Global Thermostat Using The Same". The contents of
each of the foregoing applications are incorporated herein by
reference.
Claims
What is claimed is:
1. A plurality of systems strategically placed across the globe,
and coordinated so as to collectively function for extracting
CO.sub.2 from the atmosphere to reduce the ambient concentration of
CO.sub.2 in the planet's atmosphere, the plurality of systems being
in locations geographically dispersed around the planet each
capable of producing a negative carbon dioxide effect on a planet's
atmosphere by extracting and collecting carbon dioxide from the
atmosphere under ambient conditions, each system comprises an air
contactor, wherein the air contactor comprises a porous solid
pancake shaped substrate, on the surface of which is attached an
amine, the substrate-supported amine being capable of absorbing
carbon dioxide from the ambient atmosphere, a collector chamber,
capable of receiving the substrate with the attached amine from the
air contactor, and a source of steam, operatively connected to the
collector chamber and heated from a source of process heat
remaining from a primary process using a primary energy source, to
provide steam at a temperature of less than about 120.degree. C. to
the collector chamber, for extracting and collecting carbon dioxide
from the sorbent medium and regenerating the sorbent medium, so
that the plurality of systems together can effectively extract
carbon dioxide from the atmosphere in an economically efficient
manner.
2. The plurality of systems of claim 1 wherein each of the
plurality of systems further comprises: a sequestration system that
removes the carbon dioxide from the collector chamber and isolates
the removed carbon dioxide to a location for at least one of
sequestration, storage and generation of a renewable carbon fuel or
non-fuel products such as fertilizers and construction
materials.
3. The plurality of systems of claim 2 wherein the process heat is
obtained from an adjacent source of carbon dioxide emissions.
4. The plurality of systems of claim 2 wherein the steam provided
to the collector chamber is at a temperature of not greater than
100.degree. C.
5. The system of claim 4, wherein the primary energy sources are
selected from the group of primary energy sources consisting of:
fossil fuel, geothermal, nuclear, solar, biomass and other
renewable energy sources and exothermic chemical processes whose
use for a primary process can result in a supply of process
heat.
6. The system of claim 4, wherein the location of at least some of
the systems is underground.
Description
FIELD OF THE INVENTION
The present invention relates to systems and methods for removing
greenhouse gases from an atmosphere, and in particular to systems
and methods for removing carbon dioxide from an atmosphere.
BACKGROUND OF THE INVENTION
There is much attention currently focused on trying to achieve
three energy related and somewhat conflicting energy related
objectives: 1) provide affordable energy for economic development;
2) achieve energy security; and 3) avoid the destructive climate
change caused by global warming. Many different approaches are
being considered to address climate change, including increasing
the use of clean, non polluting renewable energy sources such as
biofuels, solar, wind and nuclear, attempting to capture and
sequester the carbon dioxide emissions from fossil fuel plants, as
well as increased conservation efforts. Some of these approaches,
such as solar power, have had their large scale implementation
blocked due to their current high costs as compared to the cost of
fossil based electricity, and other approaches, such as nuclear,
are restrained by their environmental and security risks. In fact,
the infrastructure and supply for renewable energy is so
underdeveloped (e.g., only about 0.01% of our energy is provided by
solar) that there is no feasible way to avoid using fossil fuels
during the rest of this century if we are to have the energy needed
for economic prosperity and avoid energy shortfalls that could lead
to conflict.
The climate change threat caused by global warming and the more
general recognition of our need to use renewable resources that do
not harm our planet has grown steadily since the first Earth Day in
1972. It is mostly undisputed that an increase in the amount of
so-called greenhouse gases like carbon dioxide (methane and water
vapor are the other major greenhouse gases) will increase the
temperature of the planet. These greenhouse gases help reduce the
amount of heat that escapes from our planet into the atmosphere.
The higher the concentrations of greenhouse gases in the atmosphere
the warmer the planet will be. There are complicated feedbacks that
cause the amount of carbon dioxide and other greenhouse gases to
change naturally even in the absence of human impact. Climate
change throughout geological history has caused many extinctions.
The concern about the threat of human induced climate change (i.e.,
global warming) resulted in the Kyoto Protocol that has been
approved by over 165 countries and is an international agreement
that commits the developed countries to reduce their carbon
emissions.
One reason global warming is thought by the Intergovernmental Panel
on Climate Change (IPCC) to be a threat is because of the sea level
rise resulting from the melting of glaciers and the expansion of
the ocean as our planet becomes hotter. Hundreds of millions of
people who live just above sea level on islands or on the coasts
are threatened by destructive flooding requiring relocation or the
building of sea walls if the sea level rises even a meter. There is
also a threat to other species from climate change which will
destroy ecosystems that cannot adjust to the fast rate of human
caused climate change. Additional threats include increased
infectious diseases and more extreme weather as well as direct
threats from extreme heat.
We can demonstrate the challenge of dealing with global warming
using a simple model. Let C.sub.CA(Y.sub.N) represent the carbon
dioxide added to the atmosphere in year Y.sub.N in gigatonnes per
year. Similarly, let C.sub.EX(Y.sub.N) equal the amount extracted,
C.sub.EM(Y.sub.N) the amount emitted by humans and C.sub.N(Y.sub.N)
be the amount either added or removed due to natural variations in
the carbon cycle. Today, the land stores each year approximately
1.8 gigatonnes (10.sup.9 tonnes) of carbon dioxide and the ocean
approximately 10.5 gigatonnes (note carbon dioxide is 3.66 times
heavier than carbon), while the amount humans add by emissions is
about 24 gigatonnes of carbon dioxide. More generally, we have:
C.sub.CA(Y.sub.N)=-C.sub.EX(Y.sub.N)+C.sub.EM(Y.sub.N)+C.sub.N(Y.su-
b.N) (1) C.sub.A(Y.sub.N+1)=C.sub.A(Y.sub.N)+C.sub.CA(Y.sub.N)
(2)
where C.sub.A(Y.sub.N) is the amount of carbon in the atmosphere in
year Y.sub.N, 2780 gigatonnes of carbon dioxide today. Other forms
of carbon contribute to global warming, most notably methane,
although by weight they represent a small component
If C.sub.EX(Y.sub.N) is set to zero than the only way one could
possibly stop adding carbon dioxide to the atmosphere would be to
reduce our emissions to be equal to the natural uptake. However,
C.sub.N(Y.sub.N) itself varies greatly and can be a net addition to
the atmosphere from the much larger natural carbon cycle which adds
and subtracts carbon at about 750 gigatonnes of carbon per year. It
is the shifts in this natural balance that has caused climate
change before our species existed and will also continue to do so
in the future. Thus, it is clear that there is no solution that
only reduces human contributions to carbon dioxide emissions that
can remove the risk of climate change. With air extraction and the
capability to increase or decrease the amount of carbon dioxide in
the atmosphere one can in principle compensate for other greenhouse
gases like methane that can change their concentrations and cause
climate change.
Accordingly, there is a broadly recognized need for a system and
method for reducing the amount of carbon dioxide in the atmosphere
created by burning of fossil fuels and for providing a low cost,
non-polluting renewable energy source as a substitute for fossil
fuels.
SUMMARY OF THE INVENTION
A system for removing carbon dioxide from an atmosphere to reduce
global warming and which can increase availability of renewable
energy or non-fuel products such as fertilizers and construction
materials according to an exemplary embodiment of the present
invention comprises an air extraction system that collects carbon
dioxide from the atmosphere through a medium and removes carbon
dioxide from the medium by using process heat to heat the medium, a
collection system that isolates the removed carbon dioxide to a
location for at least one of sequestration, storage and generation
of a renewable carbon fuel, and one or more energy sources that
provides a supply of process heat to the air extraction system to
remove the carbon dioxide from the medium.
In at least one embodiment, the one or more energy sources are
selected from the group of energy sources consisting of: fossil
fuel, geothermal, nuclear, solar, biomass and other renewable
energy sources.
In at least one embodiment, the air extraction system comprises an
air contactor that includes the medium to absorb carbon dioxide
from the atmosphere.
In at least one embodiment, the air contactor is selected from the
group of air contactors consisting of: convection towers,
absorption pools, packed scrubbing towers, and gaseous separation
systems, some having pancake shaped area substrates with a medium
that extracts carbon dioxide from the air. In its broadest context,
the present invention contemplates structures in which the air is
passed into contact with the medium that extracts the CO2.
Currently, in the most likely embodiment the structure would have a
large area perpendicular to the air flow and be very thin in the
direction of air flow with the medium being a porous substrate on
to the surface of which the amine or alternative that binds the CO2
is attached--that medium would also have a large cross-section and
be very thin like the contactor structure that houses it).
In at least one embodiment, the medium is selected from the group
of mediums consisting of: a liquid, a porous solid, a gas and
mixtures thereof.
In at least one embodiment, the medium is an NaOH solution.
In at least one embodiment, the medium comprises an amine.
In at least one embodiment, the air extraction system collects
carbon dioxide and the sequestration system isolates the removed
carbon dioxide.
In at least one embodiment, the location is underground.
In at least one embodiment, the location is at a remote site upwind
from one or more other components of the system.
A method for removing carbon dioxide from an atmosphere to reduce
global warming and increase availability of renewable energy
according to an exemplary embodiment of the present invention
comprises the steps of: collecting air from the atmosphere;
removing carbon dioxide from the collected air by using process
heat to heat the medium that removes the carbon dioxide from the
collected air; and isolating the removed carbon dioxide to a
location for at least one of sequestration, storage and generation
of a renewable carbon fuel, wherein at least one of the collecting,
removing and isolating steps is performed using one or more
renewable energy sources.
In at least one embodiment, the step of removing comprises
absorbing the carbon dioxide using an absorber, preferably an
absorber in the form of a medium carried by a large surface area
substrate.
In at least one embodiment, the absorber is an NaOH solution.
In at least one embodiment, the absorber comprises an amine,
preferably an amine bound to the surface of (carried by) a large
surface area porous substrate.
In at least one embodiment, the step of isolating comprises at
least one of mineral sequestration or injection as a pressurized
gas into geologic formations.
The principles of the present invention can be used to provide a
global thermostat for controlling average temperature of a planet's
atmosphere, through the use of a plurality of systems according to
the principles of the present invention, each of which is capable
of producing a negative carbon dioxide effect on a planet's
atmosphere by extracting carbon dioxide from the atmosphere and
using process heat for extracting carbon dioxide from the medium
and to regenerate the sorbent (medium) for another cycle of
adsorption. Thus, the plurality of systems together can effectively
extract carbon dioxide from the atmosphere at a rate that is faster
than the rate at which the carbon dioxide is increasing in the
atmosphere (and can generate a renewable carbon fuel using the
extracted gases).
Applicants' preferred concept of extracting carbon dioxide from the
atmosphere and using process heat to separate carbon dioxide from
the collection medium is a significant way of addressing the global
warming problem, and goes against the conventional wisdom in the
art (and is counterintuitive to those in the art). Specifically,
the use of process heat to solve the global warming problem by
extracting carbon dioxide (CO2) from the low concentration ambient
air is very attractive compared to both the conventional approach
of extracting CO2 from high concentration flue gas sources and
other schemes known in the art for extracting CO2 from the ambient
atmosphere. In the former case it goes directly against
conventional wisdom that 300 times lower concentration of the CO2
in ambient atmosphere would expect it to be 300 times more
expensive since separation costs are thought to generally scale
inversely with the concentration. Thus federally funded efforts
have been directed at extracting CO2 from the flue gas emissions of
power plants (e.g. clean coal) and experts have publicly claimed
that the use of ambient air as opposed to flue gas makes no sense.
However, the large infinite size of the ambient air source compared
to the finite flue gas source and sources generally is one feature
that enables applicants' approach to be effective in spite of
conventional wisdom and practice. In the flue gas case the
emissions containing the CO2 are at a higher temperature (65-70
degrees centigrade) and therefore regeneration uses higher
temperature heat which is more costly than is needed for the cool
ambient air (approximately 25-30 degrees centigrade). There are
other benefits of applicants' approach including the ability to use
very thin separation devices that also provide further process
improvements. Thus, it could be less costly to remove CO2 by piping
the process heat to a global thermostat facility that operates on
the principles of applicants' invention, rather than cleaning up
directly its flue emissions. In addition, the applicants' approach
would produce negative carbon, actually reducing the amount of CO2
in the atmosphere, while cleaning up the flue gas would only
prevent the CO2 content in the air from increasing.
Further analysis shows that one cannot solve the global warming
problem in a timely manner to reduce the great risk it poses by
simply cleaning up large stationary fossil fuel sources like coal
plants or for that matter by conservation or use of renewables. One
needs to actually be able, as is the case in this invention, to
extract CO2 from the atmosphere ("negative carbon") thus reducing
the ambient concentration and reducing the thereat of global
warming. Other published schemes for extracting CO2 from the
ambient atmosphere have used higher temperature heat generally and
not process heat specifically and therefore have not been seriously
considered because of their high energy costs.
Additionally, it should be noted that applicants' preferred concept
for extracting carbon dioxide from the atmosphere comprises using a
large area substrate perpendicular to the air flow, which could be
porous with a high surface area, with a medium (e.g. an amine) that
removes carbon dioxide from the atmosphere and using process heat
to remove carbon dioxide from the medium. Using a relatively large
area substrate perpendicular to the direction of air flow is
particularly useful, because of the relatively low concentration of
carbon dioxide in the atmosphere (as opposed to the relatively high
concentration that would normally be found in flue gases, for
example).
These and other features of this invention are described in, or are
apparent from, the following detailed description (and accompanying
drawings) of various exemplary embodiments of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Various exemplary embodiments of this invention will be described
in detail, with reference to the following figures, wherein:
FIG. 1 is a generalized block diagram of a system for removing
carbon dioxide from an atmosphere according to an exemplary
embodiment of the present invention;
FIG. 2 is a block diagram of a system for removing carbon dioxide
from an atmosphere according to an exemplary embodiment of the
present invention;
FIG. 3 is a block diagram of an air extraction system according to
an exemplary embodiment of the present invention;
FIG. 4 is a map illustrating a global thermostat according to an
exemplary embodiment of the present invention; and
FIG. 5 is a block diagram of a system for removing carbon dioxide
from an atmosphere according to an exemplary embodiment of the
present invention;
FIG. 6 is a schematic illustration of one version of a medium for
removing carbon dioxide from an atmosphere and for removing carbon
dioxide from the medium, according to the principles of the present
invention;
FIG. 7 is a schematic illustration of another version of a medium
for removing carbon dioxide from an atmosphere and for removing
carbon dioxide from the medium, according to the principles of the
present invention;
FIG. 8 is a schematic illustration of still another version of a
medium for removing carbon dioxide from an atmosphere and for
removing carbon dioxide from the medium, according to the
principles of the present invention; and
FIG. 9 is a schematic illustration of yet another version of a
medium for removing carbon dioxide from an atmosphere and for
removing carbon dioxide from the medium, according to the
principles of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 is a generalized block diagram of a system, generally
designated by reference number 1, for removing carbon dioxide from
an atmosphere according to an exemplary embodiment of the present
invention. The system 1 includes an air extraction system 40 and a
collection system 50, that isolates the removed carbon dioxide to a
location for at least one of sequestration, storage and generation
of a renewable carbon fuel or the generation of a non-fuel product
such as fertilizer and construction materials. The air extraction
system 40 preferably incorporates any known or later-discovered
CO.sub.2 extraction method, including methods which use a medium to
absorb and/or bind CO.sub.2 from the atmospheric air by exposing
the medium to chemical, electrical and/or physical interaction with
the CO.sub.2 in the captured air. The medium may be liquid, gaseous
or solid, or a combination of liquid, gaseous and solid substances,
where in the case of solids, the substance is preferably porous.
The medium is preferably recyclable so that after the CO.sub.2 is
captured by the medium and separated from the medium for
sequestration, the medium can be reused for absorption/binding of
additional CO.sub.2. However, in other embodiments the medium may
be sequestered along with the captured CO.sub.2. As shown in FIG.
1, the separation of the CO.sub.2 from the medium, as well as other
processes such as the absorption/binding of CO.sub.2 and the
sequestration of the CO.sub.2 performed by the sequestration system
50, may be made more efficient by the addition of heat to the air
extraction system 40. In the present invention, the heat is process
heat generated e.g. by a solar energy generator, such as a solar
collector, to be described in further detail below. In other
embodiments, process heat may be provided by other types of energy
sources, such as, for example, fossil fuel, geothermal, nuclear,
biomass, and other renewable energy sources. The term "process
heat" as used herein refers to the lower temperature heat remaining
after the higher temperature heat has been used to generate
electricity. More generally, the term "process heat" refers to any
low temperature heat remaining after a primary process or that is
added by the process itself, such as, for example, exothermic
carbonation reactions in which carbon dioxide is stored as a
mineral or in fact when it binds to the medium and is captured.
Moreover, "process heat" may be provided from the use of sources of
energy to produce products other than power or electrical
generation. For example, primary processing such as chemical
processing, production of cement, steel or aluminum, production of
energy products like coal to liquid energy products, refining, may
use heat to drive the primary processing, and the unused heat
remaining after the primary processing or created during the
primary processing would be the process heat of such processing,
and can be used in a system or method according to the principles
of the present invention.
Applicants' preferred concept of extracting carbon dioxide from the
atmosphere and using process heat to separate carbon dioxide from
the collection medium is a significant way of addressing the global
warming problem, and goes against the conventional wisdom in the
art (and is counterintuitive to those in the art). Specifically,
the use of process heat to solve the global warming problem by
extracting carbon dioxide (CO2) from the low concentration ambient
air is very attractive compared to both the conventional approach
of extracting CO2 from high concentration flue gas sources and
other schemes known in the art for extracting CO2 from the ambient
atmosphere. In the former case it goes directly against
conventional wisdom that 300 times lower concentration of the CO2
in ambient atmosphere would expect it to be 300 times more
expensive since separation costs are thought to generally scale
inversely with the concentration. Thus federally funded efforts
have been directed at extracting CO2 from the flue gas emissions of
power plants (e.g. clean coal) and experts have publicly claimed
that the use of ambient air as opposed to flue gas makes no sense.
However, the large infinite size of the ambient air source compared
to the finite flue gas source and sources generally is one feature
that enables applicants' approach to be effective in spite of
conventional wisdom and practice. In the flue gas case the
emissions containing the CO2 are at a higher temperature (65-70
degrees centigrade) and therefore regeneration uses higher
temperature heat which is more costly than is needed for the cool
ambient air (approximately 25-30 degrees centigrade). There are
other benefits of applicants' approach including the ability to use
very thin separation devices that also provide further process
improvements. Thus, it could be less costly to remove CO2 by piping
the process heat to a global thermostat facility that operates on
the principles of applicants' invention, rather than cleaning up
directly its flue emissions. In addition, the applicants' approach
would produce negative carbon, actually reducing the amount of CO2
in the atmosphere, while cleaning up the flue gas would only
prevent the CO2 content in the air from increasing.
Further analysis shows that one cannot solve the global warming
problem in a timely manner to reduce the great risk it poses by
simply cleaning up large stationary fossil fuel sources like coal
plants or for that matter by conservation or use of renewables. One
needs to actually be able, as is the case in this invention, to
extract CO2 from the atmosphere ("negative carbon") thus reducing
the ambient concentration and reducing the threat of global
warming. Other published schemes for extracting CO2 from the
ambient atmosphere have used higher temperature heat generally and
not process heat specifically and therefore have not been seriously
considered because of their high energy costs.
FIG. 2 is a block diagram of a system, generally designated by
reference number 2, for removing carbon dioxide from an atmosphere
according to an exemplary embodiment of the present invention. The
system 2 includes a solar collector 10, an optional supplemental
energy source 20, a power generator 30, an air extraction system 42
and a collection system 50. Each of these components of the system
1 are explained in detail below.
The solar collector 10 may be any known or future-discovered solar
energy collection system, which may include solar energy collection
units, such as, for example, concentrated solar power parabolic
mirrors, and concentrated solar power towers. As is known in the
art, the solar collector 10 converts solar energy to thermal
energy, which may be used to drive the power generator 30. Residual
thermal energy (i.e., process heat) may be used to drive the air
extraction system 42 and/or the collection system 50. For example,
the process heat may be used to improve the efficiency of chemical
and/or physical reactions used in the air extraction system 42 to
absorb CO.sub.2 from the air and/or to drive off the CO.sub.2 from
the medium. In addition, in other exemplary embodiments, as shown
by the dashed arrows in FIG. 2, direct heat from the solar
collector 10 may be used to drive the air extraction system 42
and/or the collection system 50.
The power generator 30 may be, for example, a thermal power
generator that converts the thermal energy provided by the solar
collector to electricity. As is known in the art, the suns heat may
be focused on a medium, such as molten salts, that is then used to
generate high temperature, high pressure steam that drives a
turbine to generate electricity. The generated electricity may then
be used to power the other components of the system 2, in addition
to providing power to the general population as part of a power
grid. In this regard, the thermal energy provided by the solar
collector 10 may be supplemented by energy generated by the
supplemental energy source 20. For example, the supplemental energy
source 20 may be a waste incineration plant, which provides
additional thermal energy to drive the power generator 30. Also, it
should be appreciated that any other type of renewable energy
source may be used in addition to solar energy, and preferably a
renewable energy source that produces heat as a precursor to the
generation of electricity. Other potential renewable energy sources
to be used in addition to solar energy include, for example,
nuclear, biomass, and geothermal energy sources.
Alternatively, the power generator 30 may be any known or later
discovered fossil fuel facility (plant) that relies on the burning
of fossil fuels, such as, for example, coal, fuel oil, natural gas
and oil shale, for the generation of electricity. The power
generator may also be for a purpose other than generating
electricity (for example the power generator could be for chemical
processing, or various other purposes like producing aluminum). The
thermal energy produced by the fossil fuel power plant 30 is used
to produce electricity and the residual thermal energy (i.e.,
process heat) may be used to drive the air extraction system 42
and/or the sequestration system 50. For example, the process heat
from the fossil fuel power plant 30 may be used to improve the
efficiency of chemical and/or physical reactions used in the air
extraction system 42 to absorb CO.sub.2 from the air and/or to
drive off the CO.sub.2 from the medium. The residual heat provided
by the fossil fuel power plant 30 may be supplemented by energy
generated by a supplemental energy source. For example, the
supplemental energy source may be a waste incineration plant or a
renewable energy source, such as, for example, solar, nuclear,
biomass, and geothermal energy sources, which provides additional
thermal energy to drive the air extraction system 42 and/or the
collection system 50. Process heat from the supplemental energy
source may also be used to drive the air extraction system 42
and/or the collection system 50.
Moreover, as described above, "process heat" may be provided from
the use of sources of energy to produce products other than power
or electrical generation. For example, primary processing such as
chemical processing, production of cement, steel or aluminum,
refining, production of energy products like coal and liquid energy
products, may use heat to drive the primary processing, and the
unused heat remaining after the primary processing or created
during the primary processing would be the process heat of such
processing, and can be used in a system or method according to the
principles of the present invention.
FIG. 3 is a block diagram of the air extractor system 42 useable
with the system 2 according to an exemplary embodiment of the
present invention. The air extractor system 42 includes an air
contactor 41, a causticizer 43, a slaker 45, a calciner 47 and a
capture unit 49. The air contactor 41 may use a sorbent material to
selectively capture CO.sub.2 from the air, and may be composed of
any known or later-discovered contactor structures, such as, for
example, large convection towers, open, stagnant pools, and packed
scrubbing towers. In the present embodiment, the sorbent material
may be sodium hydroxide (NaOH), which readily absorbs CO.sub.2 from
the air. It should be appreciated that other known or
future-discovered capture methods may be used, such as, for
example, chemical absorption, physical and chemical adsorption,
low-temperature distillation, gas-separation membranes,
mineralization/biomineralization and vegetation. As a further
example, as known in the art, aqueous amine solutions or amine
enriched solid sorbents may be used to absorb CO.sub.2. Preferably,
the sorbent material is regenerated and the capture method requires
less than about 100-120.degree. C. heat to regenerate the sorbent
material.
In this embodiment, at the air contactor 41, CO.sub.2 may be
absorbed into an NaOH solution forming sodium carbonate
(Na.sub.2CO.sub.3), e.g. in the manner described by Stolaroff et
all in an article entitled "A pilot-scale prototype contactor for
CO2 capture from ambient air: cost and energy requirements", which
article can be found at
www.ucalgary.ca/.about.keith/papers/84.Stolaroff.AirCaptureGHGT-8.p.pdf,
and is incorporated herein by reference. Of course, other known or
future-developed absorbers may also be used as an alternative or in
addition to an NaOH solution. The generated Na.sub.2CO.sub.3 is
then sent to the causticizer 43, where the NaOH is regenerated by
addition of lime (CaO) in a batch process. The resulting CaCO.sub.3
solid is sent to the calciner 47 where it is heated in a kiln to
regenerate the CaO, driving off the CO.sub.2 in a process known as
calcination. The regenerated CaO is then sent through the slaker
45, which produces slaked lime Ca(OH).sub.2 for use in the
causticizer 43.
The capture unit 49 captures the CO.sub.2 driven off at the
calciner 47 using any know or later-discovered CO.sub.2 capturing
method that is effective in the low concentrations in which
CO.sub.2 is present in the atmosphere and that needs only low
temperature heat for regeneration. For example, the capture unit 49
may use an amine based capture system, such as the system described
in Gray et al U.S. Pat. No. 6,547,854, dated Apr. 15, 2003, and
also Sirwardane U.S. Pat. No. 6,908,497, dated Jun. 21, 2005, both
of which are incorporated herein by reference. The capture unit 49
may also compress the captured CO.sub.2 to liquid form so that the
CO.sub.2 may be more easily sequestered.
The collection system 50 isolates the removed carbon dioxide to a
location for at least one of sequestration, storage and generation
of a renewable carbon fuel or the generation of a non-fuel product
such as fertilizer and construction materials. The collection
system 50 may use any known or future-discovered carbon,
sequestration and/or storing techniques, such as, for example,
injection into geologic formations or mineral sequestration. In the
case of injection, the captured CO.sub.2 may be sequestered in
geologic formations such as, for example, oil and gas reservoirs,
unmineable coal seams and deep saline reservoirs. In this regard,
in many cases, injection of CO.sub.2 into a geologic formation may
enhance the recovery of hydrocarbons, providing the value-added
byproducts that can offset the cost of CO.sub.2 capture and
collection. For example, injection of CO.sub.2 into an oil or
natural gas reservoir pushes out the product in a process known as
enhanced oil recovery. The captured CO.sub.2 may be sequestered
underground, and according to at least one embodiment of the
invention at a remote site upwind from the other components of the
system 2 so that any leakage from the site is re-captured by the
system 2.
In regards to mineral sequestration, CO.sub.2 may be sequestered by
a carbonation reaction with calcium and magnesium silicates, which
occur naturally as mineral deposits. For example, as shown in
reactions (1) and (2) below, CO.sub.2 may be reacted with
forsterite and serpentine, which produces solid calcium and
magnesium carbonates in an exothermic reaction.
1/2Mg.sub.2SiO.sub.4+CO.sub.2.dbd.MgCO.sub.3+1/2SiO.sub.2+95
kJ/mole (1)
1/3Mg.sub.3Si.sub.2O.sub.5(OH).sub.4+CO.sub.2.dbd.MgCO.sub.3+2/3SiO.sub.2-
+2/3H.sub.2O+64 kJ/mole (2)
Both of these reactions are favored at low temperatures. In this
regard, both the air capture and air sequestration processes
described herein may use electricity and/or thermal energy
generated by the solar collector 10 (or other renewable energy
source) to drive the necessary reactions and power the appropriate
system components. In an exemplary embodiment of the present
invention, a high temperature carrier may be heated up to a
temperature in a range of about 400.degree. C. to about 500.degree.
C. to generate steam to run a generator for electricity, and the
lower temperature steam that exits from the electrical generating
turbines can be used to drive off the CO.sub.2 and regenerate the
sorbent (e.g., NaOH). The temperature of the high temperature heat,
the generated electricity and the temperature of the lower
temperature process heat remaining after electricity production can
be adjusted to produce the mix of electricity production and
CO.sub.2 removal that is considered optimal for a given
application. In addition, in exemplary embodiments, still lower
temperature process heat that emerges out of the capture and
sequestration steps may be used to cool equipment used in these
steps.
One or more systems for removing carbon dioxide from an atmosphere
may be used as part of a global thermostat according to an
exemplary embodiment of the present invention. By regulating the
amount of carbon dioxide in the atmosphere and hence the greenhouse
effect caused by carbon dioxide and other gas emissions, the system
described herein may be used to alter the global average
temperature. According to at least one exemplary embodiment of the
present invention, several carbon dioxide capture and sequestration
systems may be located at different locations across the globe so
that operation of the multiple systems may be used to alter the
CO.sub.2 concentration in the atmosphere and thus change the
greenhouse gas heating of the planet. Locations may be chosen so as
to have the most effect on areas such as large industrial centers
and highly populated cities, or natural point sources of CO.sub.2
each of which could create locally higher concentrations of
CO.sub.2 that would enable more cost efficient capture. For
example, as shown in FIG. 4, multiple systems 1 may be scattered
across the globe, and international cooperation, including, for
example, international funding and agreements, may be used to
regulate the construction and control of the systems 1. In this
regard, greenhouse gases concentration can be changed to alter the
average global temperature of the planet to avoid cooling and
warming periods, which can be destructive to human and ecological
systems. During the past history of our planet, for example, there
have been many periods of glaciation and rapid temperature swings
that have caused destruction and even mass extinctions. Such
temperature swings in the future could be a direct cause of massive
damage and destabilization of human society from conflicts
resulting from potential diminished resources. The global
thermostat described herein may be the key to preventing such
disasters in the decades to come.
FIG. 5 is a block diagram of a system, generally designated by
reference number 100, for removing carbon dioxide from an
atmosphere according to another exemplary embodiment of the present
invention. The system 100 includes a renewable energy source 110,
an optional supplemental energy source 120, a power generator 130,
an air extraction system 142 and a collection system 150. The
present embodiment differs from the embodiment of FIG. 2 in that
the renewable energy source 110 may be any known or
future-discovered energy source besides solar, such as, for
example, nuclear, geothermal, and biomass energy sources.
Preferably, the renewal energy source produces thermal energy,
which can be used to produce electricity and to improve the
efficiency of the various chemical and/or physical reactions that
take place within the air extraction system 142 and the collection
system 150. In this regard, the air extraction system 142 and the
collection system 150 may be the same as described with reference
to the previous embodiment, or may include components according to
any other known or future-discovered air extraction and collection
systems. In addition, as shown in FIG. 4 with reference to the
previous embodiment, a plurality of systems 100 may be
strategically placed across the globe, and control of the systems
100 may be coordinated so as to collectively function as a global
thermostat.
FIGS. 6-9 are schematic illustrations of several ways that carbon
dioxide can be removed from an atmosphere, according to the
principles of the present invention.
Specifically, in FIG. 6, a pair of substrate 600, 602 are
illustrated, each of which has a medium (e.g. NAOH, an amine) that
can be brought into contact with an atmosphere to remove carbon
dioxide from the atmosphere. The substrates 600, 602 are pancake
shaped (in the sense that they are relatively large area compared
to their thickness) oriented vertically, and can each be relatively
large (in surface area) and relatively thin (e.g. on the order of a
few millimeters, and preferably not thicker than a meter). Each
substrate can move (e.g. by a pulley system (not shown) between an
upper position in which carbon dioxide laden air is brought into
contact with the medium carried by the substrate to remove carbon
dioxide from the air, and a lower position in which process heat is
directed at the substrate to remove carbon dioxide from the medium.
The substrates 600, 602 are porous with large surface areas, so
that air directed at a substrate can flow through the substrate.
When a substrate is in an upper position (e.g. the position of
substrate 600), carbon dioxide laden air is directed at the
substrate (e.g. by a fan 604 shown in dashed lines), so that as the
air flows through the substrate, the carbon dioxide contacts the
medium and is substantially removed from the air. Thus, carbon
dioxide laden air is directed at and through the substrate so that
carbon dioxide comes into contact with the medium, carbon dioxide
is substantially removed from the air by the medium, and air from
which the carbon dioxide has been substantially removed is directed
away from the substrate. When a substrate is moved to the lower
position (e.g. the position of substrate 602), process heat is
directed at the substrate (e.g. via a fluid conduit 606), and
carbon dioxide is removed (drawn off) by a source of fluid that is
directed at the substrate (in the direction shown by arrow 608) and
a source of suction 610 by which carbon dioxide that has been
removed from the medium is drawn away from the substrate. The
substrates 600, 602 can alternatively move between the upper and
lower positions, so that the substrate in the upper position is
removing carbon dioxide from the air and carbon dioxide is being
removed from the substrate in the lower position. It should be
noted that rather than the fan, if there are strong winds available
natural wind flows can be used to drive the air through the
substrate. In addition, as described below, the fan can be replaced
with a solar driven source (or by either wind or thermally-driven
air currents), in which case the efficiency and cost reduction of
extraction of carbon dioxide from atmospheric air can be further
improved. Moreover, rather than switching the positions of the
substrates, the means for generating the air flows, the flow of
process heat, and the flow of carbon dioxide away from the
substrate can be switched as carbon dioxide is captured from the
air and then extracted from the medium, as will be readily apparent
to those in the art.
FIG. 7 is a schematic illustration of another version of a medium
for removing carbon dioxide from an atmosphere and for removing
carbon dioxide from the medium, according to the principles of the
present invention. Specifically, in FIG. 7, a pair of substrates
700, 702 are illustrated, each of which has a medium (e.g. NAOH, an
amine) that can be brought into contact with an atmosphere to
remove carbon dioxide from the atmosphere. The substrates 700, 702
are oriented horizontally, and can each be relatively large (in
surface area) and relatively thin (e.g. on the order of millimeters
or centimeters). Each substrate can move horizontally (e.g. by a
pulley system (not shown) between an air extraction position in
which carbon dioxide laden air is brought into contact with the
medium carried by the substrate to remove carbon dioxide from the
air, and a carbon extraction position in which process heat is
directed at the substrate to remove carbon dioxide from the medium.
The substrates 700, 702 are porous, so that air directed at a
substrate can flow through the substrate. When a substrate is in an
air extraction position (e.g. the position of substrate 700),
carbon dioxide laden air is directed at the substrate (e.g. by a
fan 704 shown in dashed lines), so that as the air flows through
the substrate, the carbon dioxide contacts the medium and is
substantially removed from the air. Thus, carbon dioxide laden air
is directed at and through the substrate so that carbon dioxide
comes into contact with the medium, carbon dioxide is substantially
removed from the air by the medium, and air from which the carbon
dioxide has been substantially removed is directed away from the
substrate. When a substrate is moved to the carbon extraction
position (e.g. the position of substrate 702), process heat is
directed at the substrate (e.g. via a fluid conduit 706), and
carbon dioxide is removed (drawn off) by a source of fluid that is
directed at the substrate (in the direction shown by arrow 708) and
a source of suction 710 by which carbon dioxide that has been
removed from the medium is drawn away from the substrate. The
substrates 700, 702 can alternatively move between the air
extraction and carbon extraction positions, so that the substrate
in the air extraction position is removing carbon dioxide from the
air and carbon dioxide is being removed from the substrate in the
carbon extraction position It should be noted that rather than the
fan, if there are strong winds available natural wind flows can be
used to drive the air through the substrate. In addition, as
described below, the fan can be replaced with a solar driven source
(or by either wind or thermally-driven air currents), in which case
the efficiency and cost reduction of extraction of carbon dioxide
from atmospheric air can be further improved. Moreover, rather than
switching the positions of the substrates, the means for generating
the air flows, the flow of process heat, and the flow of carbon
dioxide away from the substrate can be switched as carbon dioxide
is captured from the air and then extracted from the medium, as
will be readily apparent to those in the art.
The version of the invention shown in FIG. 9 is generally similar
to the horizontally oriented version of FIG. 7, but in the version
of FIG. 9, rather than a fan being the source that moves the carbon
laden air through the substrate in the air extraction position
(e.g. substrate 900), there is a source of gas flow that is
generated from a solar heating tower or chimney (shown
schematically at 912 in FIG. 9). A solar chimney can be generated
by heating an air mass with the sun. The solar chimney would have a
"skirt" (shown in dashed lines 913 in FIG. 9) that enables the
solar heated air to be concentrated in the chimney. Thus, a solar
field with a solar chimney can be associated with a system and
structure that removes carbon dioxide from the atmosphere and
removes carbon dioxide from a medium in the manner shown and
described in connection with FIG. 7. However, rather than a fan 704
as the primary driver of carbon dioxide laden air at the substrate,
the carbon dioxide laden air is heated by solar energy and that air
is allowed to rise in the solar funnel or tower 912. Because of the
tendency for the hot air to rise, an upward draft is generated,
that would carry with it carbon dioxide laden air, and the
substrate 900 would be positioned in the way of that upward draft.
Thus, the carbon dioxide laden air would be directed through the
substrate 900 in the air extraction position, and carbon dioxide
would be removed from the substrate 902 in the carbon extraction
position in the same way as shown and described in connection with
FIG. 7. By driving the extraction of carbon dioxide from air by
solar energy, the costs of extraction are further reduced, and the
overall operation is highly renewable. Of course, provision would
need to be made for those periods when the sun didn't shine, and
some form of driver similar to the fan 704 (FIG. 7) would be
needed. But in any case, having periods in which, instead of the
fan, replacing the fan with a solar driven source (or by either
wind or thermally-driven air currents), the efficiency and cost
reduction of extraction of carbon dioxide from atmospheric air can
be further improved.
FIG. 8 is a schematic illustration of yet another version of a
medium for removing carbon dioxide from an atmosphere and for
removing carbon dioxide from the medium, according to the
principles of the present invention. In FIG. 8, the medium from
which carbon dioxide is removed from atmospheric air and from which
carbon dioxide is removed from the medium is disposed on a
continuously moving substrate 800. The substrate moves through an
air extraction zone 814, where carbon dioxide laden air is directed
at and through the substrate (which is also porous as with the
prior embodiments) so that carbon dioxide is removed from the air.
The substrate 800 then moves to a carbon extraction zone 816, where
process heat is directed at the substrate and carbon is drawn away
from the substrate in the manner described above in connection with
FIGS. 6, 7. Then, the substrate 800 moves to and through a heat
exchange zone 818 where the temperature of the substrate is lowered
(e.g. by the air that flowed through the substrate in the air
extraction zone, and by any additional cooling device that may be
useful in reducing the temperature of the substrate to a level that
enables it to efficiently remove carbon dioxide from the air when
the substrate moves back through the extraction zone 814. In
addition, the system of FIG. 8 may have another carbon extraction
zone 816, where process heat is directed at the substrate and
carbon is drawn away from the substrate in the manner described
above in connection with FIGS. 6, 7.
It should also be noted that in all of the versions of the
invention described above, the removal of carbon dioxide from the
air can be at least partially performed under non equilibrium
conditions. Additionally, it should be noted that applicants'
preferred concept for extracting carbon dioxide from the atmosphere
comprises using a relatively thin, large surface area substrate
with a medium (e.g. an amine) that removes carbon dioxide from the
atmosphere and using process heat to remove carbon dioxide from the
medium. Using a relatively large area substrate perpendicular to
the direction of air flow is particularly useful, because of the
relatively low concentration of carbon dioxide in the atmosphere
(as opposed to the relatively high concentration that would
normally be found, e.g. in flue gases).
While this invention has been described in conjunction with the
exemplary embodiments outlined above, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, the exemplary embodiments of
the invention, as set forth above, are intended to be illustrative,
not limiting. Various changes may be made without departing from
the spirit and scope of the invention.
* * * * *
References